


death is not the final frontier

by mahemma



Series: random crossovers [3]
Category: Danny Phantom, Justice League & Justice League Unlimited (Cartoons)
Genre: Full Ghost Danny Fenton, Gen, Ghost King Danny Fenton, John is thirsty, Not Beta Read, dannys obsession is space, flash is here for a free piggyback ride, j'onn is patient, literally every league member is confused but are going with it, rip the fright knight he was just trying to be a responsible servant
Language: English
Status: Completed
Published: 2020-11-03
Updated: 2020-11-03
Packaged: 2021-03-09 04:01:38
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,834
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27358444
Author URL: https://archiveofourown.org/users/mahemma/pseuds/mahemma
Summary: The Justice League turn to John Constantine when faced with a ghost problem none of them are equiped for fight. John, in turn, asks the next best person. After dragging the League through a dimension none of them can walk in, of course.
Relationships: Danny Phantom & Fright Knight
Series: random crossovers [3]
Series URL: https://archiveofourown.org/series/1989715
Comments: 27
Kudos: 647
Collections: You haven’t lived if you haven’t read this





	death is not the final frontier

**Author's Note:**

> Soooo in this, instead of danny turning into a halfa, he turned into a full ghost and got yeeted into the ghost zone. His parents were distraught that their invention killed their son, and they ultimately decided to dismantle the portal to prevent anything else from happening (danny was never particularly ambitious, they never thought that he would turn into a ghost). Dannys never been back to amity since it happened, and hes spent most of his time exploring the various doors and dimensions in the Zone. pariah dark still got loose and he somehow defeated him and became the ghost king. I would say hes been dead for like… 7 years?? And hes been king for maybe 3??
> 
> Danny has only been king for a few years, but the ghost zone connects dimensions, so he’s not from the JLU dimension. Daniel Fenton does not exist in the Justice League’s dimension. At least, not in any way they can find.

“I may know a guy,” Constantine volunteered reluctantly. The Justice League members around him, the majority inspecting the various artifacts scattered around his living room, all turned to him in unison. He held his hands up. “I _may_ know a guy. I don’t know if they’ll help with anything this… petty.”

“ _Petty?_ ” Hawkgirl snarled. “ _Ghosts_ of people that are _still alive_ having been showing up and wreaking havoc. How is that in any way _petty?_ ”

“Well,” Constantine sighed, “they’re not the most… accessible. I only know how to get to them because I stole a page from a book on the politics of the afterlife from Thanatos.”

Wonder Woman raised an eyebrow. “You _stole_ from the god of death? You’re lucky he’s the god of non-violent deaths, otherwise he would have sent you directly to Tartarus.” He shrugged, not saying anything. He knew it was true.

“We contacted you because this kind of magic is beyond the capabilities of any current league member. If you think that someone could help us, take us to them,” Batman said, narrowing his eyes at Constantine.

Looking a little unsure, Constantine nodded. “Alright, but you all need to listen to _everything_ I say, and be _respectful_. I’m not entirely sure how… merciful they are, and I’d rather not be responsible for the death of the Justice League.”

“Oh, come on, he can’t be _that_ dangerous! We can take whoever it is,” chimed Flash, looking up from where he was speeding through one of Constantine’s many books.

Constantine stalked over, snatching the book from the speedster. “Don’t read that, it’s cursed! Anyone who reads too much will find themselves trapped in its pages.

“And I don’t think you’ll want to say that in front of the Ghost King, speedy.”

\--------------

After stepping through the glowing green portal Constantine opened, they looked around. The space around them was a darker green than the portal. There was very little around them aside from some far-off asteroids and doorways slowly drifting past. The main thing the League noticed was the distinct lack of solid ground.

“Welcome, Justice League, to the Infinite Realm, known as the Ghost Zone,” Constantine spread his arms out, “Don’t touch the doors, they lead to random places across time and space. Don’t ask anyone how they died, most ghosts died violently. What else… oh yeah, don’t pet anything, don’t disturb any plants, and for God’s sake _don’t_ get separated. The only way to travel is by flying, and the _Infinite_ Realm is _infinitely_ large. Last thing: do _not_ assume age is equal to maturity. Some of these ghosts look like toddlers but they’ve been around for longer than you’ve been a twinkle in your dad’s eye. Any questions? No? Good. Pick me up, Ken, we’ve gotta find a ghost willing to show us the way.”

Superman blinked as Constantine shoved himself in his arms, muttering “Ken?” before shaking his head and going to grab Batman. Batman quietly side-stepped him, walking towards Wonder Woman. Flash, on the other hand, flung himself onto Martian Manhunter’s back. He was beaming as he shouted “Dibs! I call dibs on a piggyback ride from J’onn!” His legs were obligingly held by his steed as he wiggled into a more comfortable position.

It took a few minutes to get everyone situated, and they set off in search of a guide as soon as they could.

(Constantine may or may not have looked extra smug whilst being carried bridle-style by the Man of Steel.)

\--------------

They didn’t get far before being stopped by a young man riding a motorcycle.

Aside from his sickly green eyes and the fact that he was seemingly driving on _nothing_ , there wasn’t anything that indicated to the leaguers that he was a ghost. The girl with him, on other hand, was much more obviously not human. Her green hair, red eyes, and greenish skin attested to that. Both of them looked like the stereotypical biker-and-his-girlfriend combo from the 1950s.

“Well, well, well,” the man said, “Humans? In the Zone? That’s some pretty bad luck.”

The girl rolled her eyes, “Wow, so original Johnny. I’m impressed.”

“Shut up, Kitty! I was trying to look cool!”

“Well, you _really_ nailed that, making a pun they wouldn’t even understand.”

“Excuse me,” Constantine cut in, “but we wanted to request an audience with the king.”

That quickly got their attention. Johnny sneered, his shadow growing slightly darker, “What do you want with him? Humans don’t fall under his jurisdiction until _after_ they’ve died, and you all look pretty alive to me.”

Kitty smirked. “We could always change that.” All of the leaguers tensed, preparing for a potential attack.

Constantine waved his hands, “That won’t be necessary. At least three of these guys aren’t human, so they don’t fall under the king’s jurisdiction at all. We would really appreciate it if you could show us how to get to him, please.”

Kitty looked contemplative. “Not human? Are they aliens or something else?”

“Three of us are aliens, ma’am, and one of us is an Amazonian demigoddess,” Superman piped in, hoping to relieve some of the tension.

Johnny and Kitty grinned. Kitty continued, “Lucky you, King Danny _loves_ aliens. Space is his obsession. He would die again for an opportunity to talk to real aliens. Alright, we’ll show you the way. Calm down, Shadow.” She snapped the last part to the shadow of the bike, which had been steadily getting darker and darker as the tension increased. A tongue emerged from it and blew a raspberry at Kitty. She ignored it.

“Follow us,” Johnny said to them before revving his engine and speeding away.

\--------------

“Um, are we just going to ignore the fact that his shadow _has a tongue?_ Is that normal here?”

\--------------

The king’s castle was relatively small, considering his position. It was shaped to look a stereotypical flying saucer, various gadgets and telescopes peaking towards the endless space of the Infinite Realm. It was shrouded in darkness, contrasting with the green of the space around it. Mainly black and silver, there were various glowing spots in the darkness surrounding it, emulating stars in the night sky. There were numerous nebulas and galaxies depicted, the oranges and purples and blues captivating to those looking at it. Overall, it looked as if a spaceship – along with the space surrounding it – had been plucked straight from its flight.

“It’s… smaller than I expected,” Flash said, awed by the beautiful sight.

“Why would it be bigger? This is the king’s lair, only him and the Fright Knight stay here,” Kitty raised her eyebrows. “The king doesn’t have any servants besides his Knight, anyway.”

“The Fright Knight?” Green Lantern questioned, raising a skeptical eyebrow.

Johnny and Kitty shared an uneasy look. “He’s the spirit of Halloween and the king’s most loyal servant. He’s, uh… he’s a lot more likely to attack you than the king is. He’ll do anything for the king,” Johnny reluctantly offered.

“You may be able to get on his good side. He doesn’t look like it, but he’s _really_ into poetry… actually that’s pretty obvious,” Kitty cut in. “Either way, you have to go through him to get to the king.”

Suddenly, a glowing green sword was speared into the air in front of Johnny’s bike. It gave off a green miasma, and more than one person felt their heart rate spike at the sight.

“And that’s our cue to leave,” Johnny said, “Good luck talking to King Danny!” Driving away as soon as he finished speaking, the leaguers weren’t able to say anything.

“FOOL!” A deep voice yelled, slightly echoing at the edges. “You cannot run from the FRIGHT KNIGHT! Return and explain your presence!” Johnny and Kitty were now a speck in the distance.

The leaguers turned to look at the supposed ‘Fright Knight’. He was tall with ankle length flaming purple hair and glowing green eyes. His face was obscured by his helmet, spikes decorating the dark metal. In fact, all of his armor was dark, mainly black with gray boots, pauldrons, helm, skirt, and flaming gauntlets. There was a bright white skull decorating his skirt. As they scrutinized him, he held his hand out towards the sword, which promptly flew back to his hand.

“You!” He pointed towards Batman. “Tell me, dark one, why do you request the king’s presence? Be forthright and I might not strike you from existence!”

Batman straightened as much as he could while dangling from Wonder Woman’s forearms. “We wanted to request an audience with your king. Someone in our world has been creating ghosts artificially, and we are out of our depth with dealing with them. We hoped that the king would be willing to help us.” He sounded more confident than the rest felt. Would the king really be so willing to help them? Only time would be able to tell.

The Knight tilted his head, considering the dark knight’s words. He nodded to himself. “King Daniel will want to hear of such phenomena, BUT!” He raised his sword again, pointing at them and sending an unexpected shiver down all of their spines. “If you are being dishonest, I will send you to face your worst fears in eternal unrest!”

Batman nodded solemnly, his mouth set in a grim line. With that, the Fright Knight turned, shouting “Come forth and the king shall show you what his help is worth!” They followed behind him, keeping a healthy distance between them and the Knight.

“Did anyone feel scared when he pulled out his sword? I mean, I’m not saying getting scared isn’t a normal response to a ghost holding you at sword point, but that was _way_ scarier than I would have usually found it,” Flash whispered to the others, hoping someone would be able to answer.

“It seems as if his blade is able to invade the minds of those surrounding him, projecting feelings of terror and helplessness,” Martian Manhunter murmured.

Batman hummed. Constantine cut in, “He also said that he would ‘send us to face our worst fears’, so I think it’s safe to assume he has a more than mild effect on the mind. He may even be able to physically send us somewhere, as dimension travel is pretty normal here.”

They all went silent after that. The Knight let them into the ship, where almost everyone was set back onto their feet. No one spoke as the Knight led them through the hallways of the ship, turning at seemingly random intervals.

A couple seconds passed before Flash, still happily sitting on Martian Manhunter’s back, broke the silence.

“So, uh, Mr. Knight, sir, I’ve never properly met royalty, so how do I, uh, address King Daniel? I don’t want to offend anyone…” Flash trailed off as the Knight turned his gaze on the speedster.

“Excellent question, Fairhead! A king should be addressed exclusively as ‘Your Majesty’ and ‘sir’. Do not touch him casually, and do not speak informally. He should be greeted with a slight bow by the men, and a curtsy by the women. And lastly,” he swept a nasty glare to everyone else, “King Daniel may be lenient with how he is treated, but I will NEVER let any _peasant_ sully his Royal Majesty. My threat from earlier still stands.”

Everyone nodded with various levels of urgency.

“Also,” the Knight stated as he continued to walk, “it is alright to address me as ‘Fright Knight’, or even as ‘Knight’. Normally, it is appropriate to address a knight as ‘Sir’, but I do not want to infringe on the Majesty’s titles.” With that stated, he stopped in front of large double doors. He knocked quickly before calling out, “Your Majesty, there is a group of humans requesting an audience with you!”

They all held their breath, hearing a quiet voice say “Come in!” The voice was… younger than they thought a king would sound like. Without a touch from the Knight, the doors opened and revealed something similar to the Watchtower’s monitor room. The Knight and the heroes walked in, the Knight standing at attention in front of them.

A young man sat sideways on a large captain’s chair, attention focused on the cellphone in his hands. The young ghost – King Daniel? – looked…very young, maybe fourteen or fifteen. White haired flowed from his head, drifting around as if underwater, his tan skin contrasting with his glowing green eyes. On his head was a floating crown, green flames spouting from it. His clothes were casual – black pants and combat boots, a white hoodie with a black symbol resembling a ‘P’ inside of a ‘D’, and a bright green ring emblazoned with a skull on his hand. There was a cloak draped around his shoulders, but its design was hidden from the heroes’ view.

“What’s up, Fright? I couldn’t really hear what you said, someone in DOOM screamed as soon as you started speaking.” _King Daniel’s_ voice echoed, giving it a slightly eerie quality.

“Your Majesty, a group of humans have come into the Ghost Zone to request your agency. It seems that someone is manipulating the ghosts in their world, causing havoc to come unfurled.” The king’s eyes peeked up from his phone, locking on Batman before wandering to the rest of the Justice League (and Constantine). They grew wider the more he looked at them, until he finally got up with his phone clutched in his left hand.

His cloak, flaring around him as he floated up from his throne, was black on the outside but looked to be made from pure space on the inside. The stars in it twinkled and shifted, blackholes opening and closing, galaxies dying and being birthed in equal amounts. Now able to see the cloak easier, they were able to see that there were even numerous planets dotting it, each unfamiliar and with their own solar system surrounding them.

“Holy COW, is that MARTIAN MANHUNTER? Fright, that’s the Martian Manhunter! From Mars! He’s a real life, bonified ALIEN! Wait, Superman and Hawkgirl?! Where did you find _three_ aliens, Fright?! Oh Ancients, I have so many questions,” the king babbled, his eyes flicking between the three aforementioned aliens, seemingly not able to decide where to look.

The heroes, on the other hand, were speechless. This… _child_ was one of the strongest beings in the known universe? (Never mind that the kid in question was more than likely _not_ a kid, since no one was sure how long he had been dead.)

It was a sobering thought. They were all too intimately aware of the death and despair in the world, but it was another thing to be faced with a child that they had failed to protect. The knowledge that this child had had a violent enough death to turn into such a powerful ghost… none of them wanted to think about it.

“Your Majesty, I… forgot to ask for their names. HOWEVER, I digress. They have come requesting your aid, and I can only hope that their point they are able to profess.” The Fright Knight stood impossibly taller at the realization of his misstep. King Daniel managed to look away from their more unearthly teammates to send the Knight a sympathetic look.

“You kind of had to stretch for that one, huh?” The Knight said nothing. “Anyway, this is the Justice League! I’m not sure which Earth they’re from, but in almost all of them they’re superheroes! Wow, and they came to me instead of me going to them, that’s new.” King Daniel’s voice grew more and more excited as he continued to talk.

Batman stepped forward, dropping his head into a respectful bow. “Your Majesty, we came to ask- .” King Daniel raised his hand, silencing Batman.

“Hold on, there’s no need to be so formal! I know Knighty here put the fear of the Ancients into you, but I really don’t care how I’m addressed. Just Danny is fine.”

“King Danny, then,” Batman raised from his bow, “We came to ask for your help. Someone in our world is artificially creating ghosts, and no one in the League is knowledgeable enough about ghosts to stop them. We were hoping you would be able to help, in any way you can.”

King Danny’s eyes brightened. He turned to the Fright Knight, “Fright, how do you feel about a trip to their world? I can ask Cujo and Wulf to look after the Ship while we’re gone.”

The Knight huffed, “Your Majesty, it would be VASTLY inappropriate for me to-“

“Please Knighty!” King Danny’s eyes got wider and wider, his lips starting to pout. “Please, I’ll even let you stab someone!”

The more he looked at the young king, the more the Fright Knight visibly crumpled under his puppy dog eyes. He sighed, “Alright, Your Majesty.” The king cheered before he turned to the stunned heroes (and one dark arts dabbler). He was grinning so hard it displayed his slightly enlarged canines.

“How can I help?”

**Author's Note:**

> Dannys lair looks like the ops center of fenton works if it was slightly bigger and in the middle of space :))
> 
> constantine is bi he was NOT going to pass up his one chance to be cradled in the beefy arms of superman
> 
> also theres nothing really shippy about batman flying with wonder woman, I never really liked their relationship and always saw them as close friends (diana is from an island of ONLY WOMEN, if this woman isn’t a lesbian ill eat my left shoe)
> 
> did I spend way too long looking up how to address a king only for danny to throw it out the window? Mayhaps
> 
> also the fright knight being unable to stand the full force of a Cute Child is hilarious to me


End file.
